A conventional hand tool such as a wrench for outputting a torque to tighten or loosen an object such as a bolt or a nut generally includes a head and a handle wherein the head includes an engaging member with which the bolt or the nut is engaged. The user rotates the handle to output a torque to rotate the object. However, the user cannot know what value of the torque that is applied to the object so the user can only determine the torque by the feel of the force in the handle. When the torque is overly applied to the object, the teeth of the object are broken and the object is difficult to be unscrewed again. This also does not work when applies a torque to an object on a precise machine because the torque has to be strictly controlled or the structure might be damaged. A conventional torque indication device known to applicant includes a flexible member and a sensor which is connected to a first end of the flexible member and the other end of the flexible member is connected with a processing unit which calculates the amount of deformation of the flexible member to transfer the result by digits. There is a loss of about 4% of the force while being transferred through the flexible member so that the value of the torque is a rough value which does not meet requirements when used to a precise machine.
The present invention intends to provide a torque indication device wherein there are two sensors located on two end of a spring so that the two respective sensors provide respective data to the processing unit to obtain a more precise value.